We quantified the seed germination responses of chicory (Cichorium intybus L.; Asteraceae) to heat, water and salt stresses using hydrothermal time (HTT) and halothermal time (HaloTT) models. We extended the HaloTT model based on NaCl concentration to include supra-optimal temperatures. The HTT and HaloTT models enabled quantitative comparison of the effects of reduced water potentials and increased salinity on germination. Below 30 °C, the median threshold water potential permitting germination estimated by the HTT model (− 0.83 MPa) was higher than that estimated by the HaloTT model (− 1.30 MPa, after converting the median threshold NaCl concentration to osmotic potential). Ion uptake into seeds imbibed in salt solutions accounted for an average osmotic adjustment of 36% in the presence of salt stress compared to seeds imbibed in polyethylene glycol solutions. These thresholds became more positive above 30 °C with a common median ceiling temperature of 43 °C. The HaloTT models developed here accurately described germination responses to NaCl concentrations across all temperatures and incorporated both water potential and osmotic adjustment effects. With respect to seed germination, chicory could be considered as a moderately water stress tolerant species and highly tolerant to salt stress.

我们量化了菊苣（菊苣（Cichorium intybus）L .; 使用热液时间（HTT）和热液时间（HaloTT）模型来加热，水分和盐分胁迫的菊科。我们扩展了基于NaCl浓度的HaloTT模型，以包括超最佳温度。HTT和HaloTT模型能够定量比较水势降低和盐度增加对发芽的影响。在30°C以下，由HTT模型估计的中值阈值水势允许发芽（-0.83 MPa）高于HaloTT模型估计的中值阈值水允许发芽（-1.30 MPa，将中值阈值NaCl转换为渗透势后）。与在聚乙二醇溶液中吸收的种子相比，在盐胁迫下，吸收到盐溶液中吸收的种子的离子吸收平均渗透调节为36％。这些阈值在30°C以上变得更正，通常的最高天花板温度为43°C。这里开发的HaloTT模型准确描述了在所有温度下对NaCl浓度的萌发响应，并结合了水势和渗透调节作用。关于种子发芽，菊苣可以被认为是中等耐水胁迫的物种，并且高度耐盐胁迫。